Hydraulic throttle control



. F. PIERCE HYDRAULIC THROTTLE CONTROL Filed sept. 2, 1939 May l2, 1942.

ATTORNEY" f Paten-ted May l2, 1942i .UNITED srAlrEs.

TT@ F11;

RAULEC TILE CNL Erold F. Pierce, Pines Lake, N. J.,

Wright Aeronautical Corporation, a ration of New York Animation september a, 193s, serial No. nazorg-- claims. (ci. 12a-#103) 'I'his invention relates toengines and is particularly concerned with improvements in control means therefor.

The objects ofthe invention will be better understood by iirst brieiiy outlining the problem which has been solved, In aircraft engines equipped with supercharg'ers and with constant speed propellers, the amount of powerdelivered is roughly proportional to the manifold pressure in the engine induction system, and, if it be desired to operate at constant power under varyingv altitude conditions, the manifold pressure must be readjusted from time. to time. The prior art provides means for maintaining constant manifold pressure comprising a bellows device communicating with the manifold, which bellows is balanced against an ad'ustable spring. The bellows controls the engine throttle through a servo-motor so that throttle opening is automatically varied to maintain a balance of the manifold pressureagainst the spring. Manifold presmotor it, this being connected to a conventional' sure regulators of the -priorart have been inter- I connected with a manualthrttle which has not been particularly satisfactory.

-Accordingly, it is an object of this invention to provide a manual throttle control in combination with an automatic throttle regulator so arranged and organized that 'the manual lever may overcontrol the automatic regulator .at any l time and during such overcontrol will have definite positions of adjustment which correspond to the actual positions of the engine throttle,

A further object of the invention is to provide automatic means for connecting themanual throttle in response to actuation thereof, and correspondingly, to disconnect the automatic-regulator at such times as the manual throttle is in use, and to reconnect the` regulator at such Fig. 1 is an elevation of an aircraft power plant incorporating the invention, and

Fig. 2 is an enlarged section through an automatic regulator and the control mechanism of the invention.

In Fig. 1, l0 represents an engine -crankcase upon which a plurality of cylinders such as -II are secured, the crankcase including an `annular manifold I2 anda blower section I3" upon which a carburetor It is mounted, the carburetor including'a throttle actuated by a lever i5.

'11o the rear of the yblower lsectionis secured an automatic manifold pressure regulator Ifthe mechanism of which is shown in detail in the left-hand part of Fig. 2, the regulator being connected through apipe Il to the manifold i2. U'pon the regulator i6 is mounted a hydraulic `motor I8-, shown in detail in the right-handpart of Fig. 2, said motor having a piston rod lilex-4 tending from the upper end thereof which is connected to the throttle I5 by a link 2t. A piston rod 2| extends from the lower'end of the throttle leverr in the pilots cockpit through. a rod 22, a bellcrank 23, and a link 28.

Referring now to Fig.' 2,the regulator i6 comprises a housing within which are serially disposed bellows 26 and 2l separated by a partition 28. The bellows 26 connes a xed quantity of elastic duid or may be evacuated while the bellows 2i co serves to balance the manifold pressure and this spring may be adjusted as to tension by a nut Si which may if desired be provided with a re-y mote control. They spring 30 may be preset for any desired manifold pressure; 'if the actual manifold pressure is less than that desired, the partition 28 will move downwardly thus moving an arm 32 with it to actuate a servo-valve 33 slidable in a bore 3i. Fluid pressure as from the engine lubricating system isled to the regulator through a passage 36 opening between small pistons 31 and 38 forming part of the valve 33..

When, as indicated, the valve 33 is moved downwardly, iiuidpressure passes to a port 39, opening another port 80 for drainage through a port 4l to the interior of theJ housing i6, and thence back to the engine through a drain opening d2.

If the manifold pressure be too high, the valve 33 is moved upwardly connecting the oil pressure supply to the port 40 and connecting the port 39 for drainage.

The hydraulic motor, operated by the regu--l lator I6, comprises a cylinder M to which a piston is closely fitted, said piston being connected to the engine' throttle through the piston rod i9. A lower piston 46 is also engaged with-y in the cylinder M from which the piston rod 2l extends from the bottom of the motor. Suitable v packing and glands\ 4-'l, 48, and is, 50 prevent iiuid` leakage from the cylmder and also guide unicates with the manifold throughv .the ope 2Q and the `pipe Il.` A spring 30 the respective piston rods. The piston rod 2i is formed with spaced annular grooves 52 and 53 which register with drillings 54 and 55 in the lower end of the motor connected respectively to the regulator ports 46 and 39. The drilling 54 -continues beyond the piston rod 2I as a port 456 opening to the cylinder 44 Just above the top surface of the piston 46 when the latter is in its -bottom position, and in which position the rod grooves 52 and 53 open the drillings 54 and 55 respectively to the port 56 and to a port 51 leadingto the top of the cylinder 44 above the piston 45.

Accordingly, when the piston 46 is in its bottom position, fluid from the regulator I6 mayy actuatelthe motor I8 by moving the piston 45 up and down to regulate the throttle I5 and thus adjust manifold pressure so that the regulator I6 will eventually balance.

The motor I8 is provided with a bypass 60 leading from the top of the-cylinder 44 to the bottom thereof, the lower opening of said bypass being covered by the piston 46 when same is in bottom position.` The piston 46 is provided with a bore 6I closed by acheck valve 62, the valve being so disposed that fluid may iiow from the top to the bottom of the piston 'but may not flow from the bottom to the top. The bypass 66 and the check valve 62 provide the means by which the piston rod 2l may be actuated to overcontrol the regulator I6, in the following manner: Let it be assumed that the regulator has positioned the throttle about half opened wherefore the piston 45 is midway of the cylinder as shown.. .It is desired to manually operate the throttle, so the pilot moves his -throttle control to a throttle opening position whereupon the piston 46 moves upwardly and concurrently, the grooves 52 and 53 become misaligned with the regulator passages 54 and 55 to out off the regulator from the throttle motor. At the same time, the piston uncovers the bypass 60 and that fluid between the pistons 45 and 46 flows through the bypass valve 62 to the cylinder portion below the piston 46, and the pistons 45 and 46 upon continuous movement of the latter, about one another. Thereuponl these pistons are hydraulically locked together so that any movements of the manual throttle rod 22 will communicate to the throttle I5. 'I'he hydraulic lock is effective in two ways-iirst, by suction between the 'heads of the pistons 45 and 46, and second, by the fixed amount of hydraulic fluid confined above and below the pistons and in the bypass 60. For instance, if the pistons are jointly moved upward, fluid above the piston 45 flows downA through the bypass 60 and to the lower opened to the ports 56 and 51, and uid entering through the port 56 breaks the seal between the abutting faces of the pistons 45 and 46 whereby the piston 45 may be'moved by hydraulic pressure to the appropriate position as governed by the regulator I6.

'I'he arrangement above vdescribed allows the over to the regulator by manipulation-of his throttle lever without the need of bothering with an extra control which was previously necessary to turn off the automatic regulator. The invention also simplifies the control arrangement between the throttle lever, the regulator, and the throttle and allows for transition between automatic and manual throttle operations with a minimum of operating and mechanical complication. l While I have described my invention in detail in its4 present preferred embodiment, it will be' obvious to those skilled in the art, after understanding my invention, that various changes and.

modifications may be made therein without departing from the spirit or scope thereof.` I aim in theappend'ed claims to cover all such modifications and changes.

- 4I claim as my invention:

1. In combination in an engine having a throttle, automatic means for operating the throttle, manual vmeans for operating the throttle, and a connecting device for the throttle and said automatic and manual means comprising a manual means element engageable with an element of the throttle atany time, and operative when so engaged to disconnect the automatic means from the throttle, said manual means when moved to the position of complete throttle closing being disconnected from the throttle and serving to reconnect the automatic means for throttle operation.

2. In an engine having a throttle, automatic throttle adjusting means having a pair of fluid outlets the fluid pressure of which is controlled according to desired throttle opening, a cylinder having a piston including a rod extending froml one cylinder end to the throttle, said iiuid presabove and below said piston, a second piston having a rod extending from the other end of the cylinder, manual control means for operating the second piston, a bypass around the iirst piston covered by the second piston when the latter is in a throttle closing attitude, and a check valve in the second piston head permitting its advance toward the first piston but preventing separation of the pistons thereafter until the manual control means is moved to a throttle closing position whereat fluid from said automatic device enters between said pistons to thereafter afford automatic throttle operation.

3. In an engine having a throttle, automatic throttle adjusting means having a pair of uid outlets the fluid pressure of which is controlled according to desired throttle opening, a cylinder havingfa piston including a rod extending from one cylinder end to the throttle, said fluid pressure outlets ,communicating with the cylinder above and below said piston, a second piston havinga rod extending from the other end of the cylinder, manual control means for operating the second piston, a bypass around the first piston covered by the second piston when the latter is in a. throttle closing attitude, a check valve in the second piston head permitting its advance pilot'to know at a glance the general rangeof throttle opening when the throttle is under manual control, and allows him to throw the throttle toward the rst pltson but preventing separation of the pistons thereafter until the manual control means is moved to a throttle closing position whereat fluid from said automatic device enters between said pistons to thereafter afford automatic throttle operation, and valve means in the uid passages for said automatic adjusting means for isolating the means from said cylinder,

aaeacae responsive to movement of the manual control means from the throttle closing position.

4. In a. powerplant, a throttle, automatic means for adjusting the position of the throttle, manmanual means from and for reconnecting the automatic means to the throttle.

5. In a powerplant, a throttle, automatic means for adjusting the position ofthe throttle, manual throttle adjusting means, and means responsive to actuation thereof from a certain position for disconnecting said automatic means from the throttle to allow of full manually controlled throttle movement both greater and less than the -movement called for by the automatic means, said automatic means being reconnected for throttle operation upon movement of said manual means to said certain position.

6. In a powerplant, a throttle, automatic throttle adjusting means, and a manual throttle overcontrol which when actuated disconnects said automatic means from `throttle operation and connects to the throttle `for manual operation thereof.

'7. In a powerplant, a-throttle, manifold pressure responsive means for hydraulically adjusting the throttle to maintain a preset manifold pressure; said means comprising a manifold pressure actuated servo valve and a hydraulic motor controlled thereby; and a manually adjustable mechanism comprising a valve movable to close the hydraulic connection from the servo valve to the motor, and means including a hydraulic coupling for actuating the throttle during such closure.

8. A throttle control device comprising a cylinder having opposed stemmed pistons, a dual shutoff valve embodied in the stem of the lower piston,

conduits from said dual valve to opposite ends of the cylinder, a bypass between opposite cylinder ends closable by said lower piston when adjacent the lower cylinder end, and a check valve in said lower piston preventing ow therethrough in an upward direction whereby the upper piston is forced to move downward when the lower piston is moved downward.

9. A throttle control device comprising a cylinder having opposed stemmed pistons, a dual shutoil valve embodied in the stem of the lower piston,

conduits from said dual valve to opposite ends of the cylinder, a bypass between opposite cylinder ends closable by said lower piston when adjacent the lower cylinder end, a checkuvalve in said lower piston preventing flow therethrough in an upward direction whereby the upper piston is forced to move downward when the lower piston is moved downward, leading to said dual shutoff valve, said fluid pressure being operative, when said dual valve is open and the lower piston bottomed, to actuate the upper piston independently of the lower.

10. In a power plant, a throttle, manual adl justing means therefor having one inactive posiand fluid pressure means vin combination,

Vpower regulator an y tion and a plurality of active positions, automatic throttle adjusting means operable when active to adjust the throttle to all of its operating positions, mechanism connecting the throttle to said manual adjusting means in all active positions of the latter and disconnecting the throttle from said manual adjusting means in its inactive position, and mechanism to connect the throttle to said automatic means in response to movement of said manual adjusting means to said one inactive position. l i L l1. In an engine in combination, automatic means to regulate engine power to a presettable value, manually adjustable means to regulate engine power, and mechanism operated by said manual means to selectively connect the automatic means or the manual means for operation through their full ranges of adjustment to the exclusion of the other means.

l2. In an engine having an induction manifold in combination, means responsive to manifold pressure to control the manifold pressure to a presettable value, manually controllable means to vary manifold pressure, said two means being operable independently of one another, and mechanism to connect one means for operation to the exclusion of the other means.

13. In an engine having an induction manifold in combination, means responsive-to manifold pressure to control presettable value, manually controllable means to vary manifold pressure, said two means being operable independently of one another, and mechanism to connect one means for operation to the exclusion of the other means, said v,mechanism being operable toeffect said connections ln response to placement of said manually controllable means in acertain position of adjustment thereof.

14. In an engine having an induction manifold means responsive to manifold pressure to control the manifold pressure to a presettable value, manually controllable means to vary manifold pressure, said two means being operable independently of one another, and mechanism to connect one means for operation to the exclusion of the other means, said mechanism being operable to connect the automatic means for operation when the manual means is set for low power or idling operation and beingA operable to disconnect the automatic means from operationupon setting of the manual means for increasing power operation.

15. In an engine in combination, a power regulator, automatic means to regulate engine power to a selectable value, manually operable means to lregulate engine power to any available amount, said manually operable means having one inactive position, and means; actuated by movement of said manual means to said inactive position to connect the automatic means to said to disconnect the manual means therefrom; and actuated by movement of Lsaid manual means from said inactive position to disconnect the automatic means from said power regulator and to connect the manual means thereto.

, EROLD F. PIERCE.

the manifold pressure to a 

